The core of MEAN Stack is JavaScript, focus on JS because it is the language of the web. Don't limit yourself to a particular frameworks because frameworks will come and go. The language will stay.
From the perspective f getting a job, the market is flooded with JavaScript jobs so I will not be a problem. You can move to Reactjs and react native for mobile apps is better than any other JS Framework for mobiles.
JS Fullstack jobs has starting of 500,000 INR
Hope that helps !